Infrared (IR) sensor systems including pixelated IR detection areas, also referred to as focal plane arrays (FPA), are used for detecting the temperature distribution on surfaces and objects contactlessly. For this purpose, they are integrated into infrared cameras, for example, thermographic cameras or surveillance cameras.
These IR sensor systems are used in a plurality of applications. Among other things, they may be used in a sensor cluster. Such sensor clusters are generally made up of a plurality of modules which are equipped with different sensors and configurations. Such sensor modules are generally connected wirelessly. The signals are used as input variables for the control or monitoring of a room in which the system is used. Of importance in such sensor modules are the overall size and the power consumption.
The individual pixels of these infrared sensor devices typically show drift over time in offset and sensitivity. For this reason, it is necessary to carry out a recalibration on a regular basis during operation. Typically, shutters are integrated into the infrared cameras for this purpose. In these calibration methods, a metal surface of a homogeneous temperature is introduced into the beam path and the signals of all pixels are subsequently recalibrated.
The known shutters entail hardware costs for the shutter dial as well as the electric motor, higher power consumption, assembly and adjustment costs. Furthermore, they result in a relevant increase in the installation space of the sensor modules. Moreover, the mechanically movable shutter components result in a reliability risk. In addition, interfering sounds may be caused by the shutter movement during the calibration.